1 Field of the Invention
This invention relates generally to the fields of virology and molecular medicine and more specifically to antiviral peptides.
2. Background Information
Viral infections including those of herpes simplex virus (HSV) are common in the United States and around the world. Depending on socioeconomic class, anti-HSV antibodies can be identified in about 60% to 80% of the population of industrialized countries. New methods for detecting antibodies to HSV type 2 (HSV-2), which is a sexually transmitted disease, suggest that about 40 to 60 million individuals in the United States are infected with HSV-2. Based on figures for the spread of easily identified sexually transmitted diseases such as gonorrhea, it is estimated that 500,000 new cases of HSV-2 infection will occur annually.
The primary sites of HSV infection are the oral and genital mucosa. Viral replication at these sites can result in lesions such as skin vesicles or mucosal ulcers. HSV infection also can result in ocular keratitis, encephalitis and disseminated neonatal or adult infection. Recurrent outbreaks of HSV infection in a subject are common and can be induced, for example, by exposure to ultraviolet light, trauma to nerve ganglia, which harbor the latent virus, and treatment with immunosuppressive agents.
Currently, nucleoside analogs are used to treat viral infections, with acyclovir being the drug of choice for treating systemic herpes virus infection. Acyclovir can decrease the rate of recurrence in individuals plagued with frequent bouts of recurrent genital herpes. However, patients must be maintained on daily acyclovir therapy to prevent recurrence. As a result, acyclovir therapy for genital herpes is one of the more expensive treatments for a sexually transmitted disease. Nucleoside analogs also can be toxic to healthy cells and can induce resistant strains of herpes viruses, particularly in immunocompromised patients such as individuals suffering from AIDS.
HSV also causes about 500,000 cases of recurrent ocular keratitis per year and is second only to trauma as the leading cause of corneal blindness in the United States. As for other HSV infections, recurrent ocular HSV infection is treated using nucleoside analogs, with the dose and schedule of administration varying depending on the clinical classification of the disease. In general, however, treatment lasts for a minimum of 21 days and the antiviral agent is applied five times a day or every two hours, depending on the drug.
Despite treatment, healing of the cornea can take several weeks. In addition, the emergence of drug resistant virus strains during treatment can cause persistence or progression of clinical symptoms. Thus, the choice of effective antiviral agents is further limited in that these agents can induce drug resistant vital strains and cause toxicity to uninfected cells. A need exists, therefore, to identify a class of antiviral agents that are inexpensive to make and are useful for treating viral infections. The present invention satisfies this need and provides related advantages as well.